scholarly journals Stress-strain model study of ferrous tailing concrete short column restraint by hooping

Mining Scince ◽  
2019 ◽  
Vol 26 ◽  
Author(s):  
Sujuan Li ◽  
Hongzhen Kang

This paper talked about stress-strain curve of stirrup restraint ferrous tailing concrete by test and theoretical analysis. Twenty short column of 5 strength grade are contained in the test with WC30, WC35, WC40, WC45 and WC50. And the stress-strain data was achieved after the axial compression behavior test. Through the stress-strain curve, it can be found that the stress-strain relationship is similar with natural sand concrete. At the same time, it was put forward the whole stress-strain curve equation of stirrup restraint ferrous tailing concrete. The calculation results showed that the data calculating by the eqution this paper are in good agreement with the experimental data.

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Yongjei Lee ◽  
Yong-Ha Hwang

This study proposes a simple and rational stress-strain relationship model applicable to brick masonry under compression. The brick prism compression tests were conducted with different mortar strengths and with constant brick strength. From the observation of the test results, shape of the stress-strain curve is assumed to be parabola. In developing the stress-strain model, the modulus of elasticity, the strain at peak stress, and the strain at 50% of the peak stress on the descending branch were formulated from regression analysis using test data. Numerical and statistical analyses were then performed to derive equations for the key parameter to determine the slopes at the ascending and descending branches of the stress-strain curve shape. The reliability of the proposed model was examined by comparisons with actual stress-strain curves obtained from the tests and the existing model. The proposed model in this study turned out to be more accurate and easier to handle than previous models so that it is expected to contribute towards the mathematical simplicity of analytical modeling.


Author(s):  
K. J. Thompson ◽  
R. Park

The stress-strain relationship of Grade 275 steel reinforcing bar under cyclic (reversed) loading is examined using experimental results obtained previously from eleven test specimens to which a variety of axial loading cycles has been applied. A Ramberg-Osgood function is fitted to the experimental stress-strain curves to follow the cyclic stress-strain behaviour after the first load run in the plastic range. The empirical constants in the function are determined by regression analysis and are found to depend mainly on the plastic strain imposed
in the previous loading run. The monotonic stress-strain curve for the steel, with origin of strains suitably adjusted, is assumed to be the envelope curve giving the upper limit of stress. The resulting Ramberg-Osgood expression and envelope is found to give good agreement with the experimentally measured cyclic stress-strain curves.


Author(s):  
Hideo Machida ◽  
Tetsuya Hamanaka ◽  
Yoshiaki Takahashi ◽  
Katsumasa Miyazaki ◽  
Fuminori Iwamatsu ◽  
...  

This paper describes a fracture assessment method for a pipe having multiple circumferential flaws. According to Fitness-for-Service (FFS) codes for nuclear facilities published by the Japanese Society of Mechanical Engineers (JSME), the fracture strength of a high-ductility pipe having a circumferential flaw is evaluated using the limit load assessment method assuming the elastic–perfectly-plastic stress–strain relationship. In this assessment, flow stress is used as a proportional stress. However, previous experimental results [1, 2, 3] show that a crack penetrates before the entire flawed pipe section reaches the flow stress. Therefore, stress concentration at a flaw was evaluated on the basis of the Dugdale model [4], and the fracture strength of the crack-ligament was evaluated. This model can predict test results with high accuracy when the ligament fracture strength is assumed to be tensile strength. Based on this examination, a fracture assessment method for pipes having multiple flaws was developed considering the stress concentration in the crack-ligament by using the realistic stress–strain relationship (Ramberg–Osgood-type stress–strain curve). The fracture strength of a multiple-flawed pipe estimated by the developed method was compared with previous experimental results. When the stress concentration in the crack-ligament was taken into consideration, the fracture strength estimated using the Ramberg–Osgood-type stress–strain curve was in good agreement with experimental results, confirming the validity of the proposed method.


2010 ◽  
Vol 163-167 ◽  
pp. 1762-1767 ◽  
Author(s):  
Xiang Liu ◽  
Jiang Tao Kong

According to the contrast test of LC30, LC40 lightweight aggregate concrete and C30, C40 common concrete , the text researched the mechanical property of lightweight aggregate concrete and ordinary concrete in the same strength grade and obtained the regularity of stress-strain curve of lightweight aggregate concrete in different strength grade. Then we contrasted the experimental results and planning model, analysed the difference, and suggested that the standards should improve the descent stage of the stress-strain curve of lightweight aggregate concrete combined with correlative experiments data, and give the equation of the descent stage of stress-strain curves. Concrete material in axial compression is the basic physical mechanical performance of concrete material, and is the main basis for researching bearing capacity and deformation of concrete construction. The stress-strain relationship is all-around macroscopic reaction of basal compressive property . There have been many experiments work about the stress-strain relationship of lightweight aggregate concrete at home and abroad , and found the peak strain of lightweight aggregate concrete is higher than that of ordinary concrete in the context of same peak stress .In this paper, on the basis of experimental investigations of lightweight aggregate concrete , aim at the stress-strain relationship ,we have take comparison experiment about LC30,LC40 lightweight aggregate concrete and C30,C40 ordinary concrete , and sort out stress-strain curve under the condition of the shaft center being compressed, so get the average tress-strain curve of LC30,LC40 lightweight aggregate concrete , and analyse the curve.


Author(s):  
Xiuhan Yang ◽  
Sai Vanapalli

Several of the geotechnical structures constructed with unsaturated soils undergo a large deformation prior to reaching failure conditions (e.g. progressive failure of a soil slope). During this process, the shear stress in soils typically increases initially and then reduces with an increase in the shear strain. The prediction of the stress-strain relationship is critical for reasonable interpretation of the mechanical behavior of those geo-structures that undergo large deformation. This paper introduces a model based on the disturbed state concept (DSC) to predict the variation of shear stress in unsaturated soils during strain-softening process under consolidated drained triaxial compression condition. In this model, the apparent stress-strain relationship is formulated as a weighted average of a hyperbolic hardening response extending the pre-peak state stress-strain curve and a linear response extending the critical state stress-strain curve with an assumed disturbance function as the weight. The prediction procedure is described in detail and the proposed model is validated using several sets of published data on unsaturated soils varying from coarse- to fine-grained soils. Finally, a comprehensive error analysis is undertaken based on an index of agreement approach.


Author(s):  
James D. Hart ◽  
Nasir Zulfiqar ◽  
Joe Zhou

Buried pipelines can be exposed to displacement-controlled environmental loadings (such as landslides, earthquake fault movements, etc.) which impose deformation demands on the pipeline. When analyzing pipelines for these load scenarios, the deformation demands are typically characterized based on the curvature and/or the longitudinal tension and compression strain response of the pipe. The term “strain demand” is used herein to characterize the calculated longitudinal strain response of a pipeline subject to environmentally-induced deformation demands. The shape of the pipe steel stress-strain relationship can have a significant effect on the pipe strain demands computed using pipeline deformation analyses for displacement-controlled loading conditions. In general, with sufficient levels of imposed deformation demand, a pipe steel stress-strain curve with a relatively abrupt or “sharp” elastic-to-plastic transition will tend to lead to larger strain demands than a stress-strain curve with a relatively rounded elastic-to-plastic transition. Similarly, a stress-strain curve with relatively low strain hardening modulus characteristics will tend to lead to larger strain demands than a stress-strain curve with relatively high strain hardening modulus characteristics. High strength UOE pipe can exhibit significant levels of anisotropy (i.e., the shapes of the stress-strain relationships in the longitudinal tension/compression and hoop tension/compression directions can be significantly different). To the extent that the stress-strain curves in the different directions can have unfavorable shape characteristics, it follows that anisotropy can also play an important role in pipeline strain demand evaluations. This paper summarizes a pipeline industry research project aimed at evaluation of the effects of anisotropy and the shape of pipe steel stress-strain relationships on pipeline strain demand for X80 and X100 UOE pipe. The research included: a review of pipeline industry literature on the subject matter; a discussion of pipe steel plasticity concepts for UOE pipe; characterization of the anisotropy and stress-strain curve shapes for both conventional and high strain pipe steels; development of representative analytical X80 and X100 stress-strain relationships; and evaluation of a large matrix of ground-movement induced pipeline deformation scenarios to evaluate key pipe stress-strain relationship shape and anisotropy parameters. The main conclusion from this work is that pipe steel specifications for high strength UOE pipe for strain-based design applications should be supplemented to consider shape-characterizing parameters such as the plastic complementary energy.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiaohui Yuan ◽  
Huiting Guan ◽  
Yanyu Shi

Stress-strain curve can accurately reflect the mechanical behavior of materials, and it is very important for structural design and nonlinear numerical analysis. Some cube and prism specimens were made to investigate the physical and mechanical properties of steel fiber reinforced alkali activated slag concrete (AASC); test results show that the strength, Young’s Elastic Modulus, and Poisson’s ratio all increase with the increase of steel fiber content. The steel fiber reinforced AASC shows an excellent postcracking behavior. Damage evolution parameter (D) was used to describe the formation and propagation of cracks, and continuum damage evolution model of steel fiber reinforced AASC was established by Weibull and Cauchy distribution. The establishing model can well describe the geometric characteristics of the key points of the concrete materials stress-strain curve. Finally, the accuracy of the model was verified by comparing the test stress-strain relationship curve of steel fiber reinforced AASC.


2012 ◽  
Vol 450-451 ◽  
pp. 822-826
Author(s):  
Lin Zhu Sun ◽  
Tie Cheng Wang ◽  
Fang Yang

To establish complete stress-strain curve equations for confined concrete in cross-shaped columns, we designed 7 test specimens corresponding to the usable eigenvalue range of stirrup of the cross-shaped columns. We obtained the test results of the reinforced concrete cross-shaped columns through axial compression test, got the system parameters of a stress-strain model through statistical analysis of the test data, and then established stress-strain curves for confined concrete in the cross-shaped columns. This model reflects the variation rule of the stress-strain curve of confined concrete in cross-shaped columns. Compared with the stress-strain model for confined concrete in square columns, the confined concrete in cross-shaped columns has smaller peak stress, larger peak strain, and relatively steeper descending part of curve. The research results provide theorotical basis for nonlinear analysis of cross-shaped columns.


2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Keun-Hyeok Yang ◽  
Ju-Hyun Mun ◽  
Hey-Zoo Hwang

This study examined the stress-strain behavior of 10 calcium hydroxide (Ca(OH)2)-activated Hwangtoh concrete mixes. The volumetric ratio of the coarse aggregate (Vagg) and the water-to-binder (W/B) ratio were selected as the main test variables. TwoW/Bratios (25% and 40%) were used and the value ofVaggvaried between 0% and 40.0%, and 0% and 46.5% forW/Bratios of 25% and 40%, respectively. The test results demonstrated that the slope of the ascending branch of the stress-strain curve of Ca(OH)2-activated Hwangtoh concrete was smaller, and it displayed a steeper drop in stress in the descending branch, compared with those of ordinary Portland cement (OPC) concrete with the same compressive strength. This trend was more pronounced with the increase in theW/Bratio and decrease inVagg. Based on the experimental observations, a simple and rational stress-strain model was established mathematically. Furthermore, the modulus of elasticity and strain at peak stress of the Ca(OH)2-activated Hwangtoh concrete were formulated as a function of its compressive strength andVagg. The proposed stress-strain model predicted the actual behavior accurately, whereas the previous models formulated using OPC concrete data were limited in their applicability to Ca(OH)2-activated Hwangtoh concrete.


Author(s):  
K. J. Thompson ◽  
R. Park

Experimental stress-strain curves for repeated tensile loading of
 0.276 in (7 mm) diameter prestressing steel wire in the inelastic range
are presented. A mathematical model employing a modified form of the Ramberg-Osgood function is proposed to describe the cyclic stress-strain behaviour of the prestressing steel. The experimental stress-strain
results are subjected to regression analysis in order to obtain empirical expressions for the constants in the Ramberg-Osgood function. The constants are found to depend on the strain imposed in the previous loading run and the characteristics of the monotonic stress-strain curve. The stress- strain curve for monotonic loading, with suitably adjusted origin of coordinates in the case of significant reversed loads, is used to describe the envelope curve which the steel stresses cannot exceed. The proposed cyclic stress-strain model predicted the experimental curves with good accuracy.


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